金属有机骨架材料MOF-5利用C3H6选择性催化还原NO的研究

采用溶剂热法在不同温度（120、150、180℃）、不同时间（12、24、48 h）条件下制备MOF-5催化剂,利用热重分析仪（TG）、X射线衍射仪（XRD）、傅立叶红外光谱仪（FT-IR）对其进行表征,研究不同条件下MOF-5样品的水热稳定性及特征官能团、化学键等指标.结果表明,利用溶剂热法制备的MOF-5样品稳定性良好,390℃结构开始坍塌.对比FT-IR、XRD等表征结果,选择图线形状最好、出峰位置最多的120℃、24 h条件下的MOF-5样品作为载体,对其进行了Cu的负载,负载量依次为1%、3%、5%.根据TG曲线,选择在MOF-5维持稳定结构、同时与尾气排放环境中的温度较为接近的350℃作为反应温度,利用傅立叶原位红外技术考察不同负载量的Cu-MOF-5在不同温度条件下对NO吸附能力大小、吸附过程中间物的变化情况,初步研究以C₃H₆作为还原剂时的富氧HC-SCR反应的机理.根据原位红外反应结果看出,NO₃^-、—CNO、—CN是重要的中间产物,且以3% Cu负载量的催化剂中间产物变化最为丰富,催化效果最优.     

Pt颗粒负载对CeO2臭氧催化氧化甲苯的增强作用

通过铂颗粒吸附法制备得到Pt/CeO₂催化剂应用于臭氧催化氧化甲苯反应,研究了Pt颗粒负载对CeO₂臭氧催化氧化甲苯的增强作用.采用氢气程序升温还原（H₂-TPR）、氧气程序升温脱附（O₂-TPD）、X射线光电子能谱（XPS）和拉曼光谱（Raman）等手段对催化剂进行表征,结果显示,CeO₂负载Pt颗粒后,Pt与CeO₂存在相互作用,提高了CeO₂上氧空位的含量.臭氧分解实验证实了Pt/CeO₂催化剂具有更好的臭氧分解性能.臭氧催化氧化甲苯评价结果表明,Pt/CeO₂具有比CeO₂更优异的催化性能,在80 ℃时甲苯降解率、CO₂产率和臭氧分解率分别达到92.3%、92.1%和99.9%.原位拉曼进一步研究了臭氧分解生成的氧物种种类及含量,以及甲苯存在时氧物种的变化,结果表明,臭氧在氧空位上分解产生的过氧物种较为稳定,是氧化甲苯的重要活性物质.因此,Pt颗粒负载在CeO₂上能增强臭氧在催化剂上分解,并形成更多过氧物种,最终提升臭氧催化氧化甲苯的性能.     

活性炭催化臭氧氧化水中诺氟沙星

以椰壳基活性炭为催化剂,采用催化臭氧氧化工艺降解诺氟沙星(NF),优化了工艺条件,评价了催化活性,并对反应机理进行了探讨。实验结果表明:活性炭催化臭氧氧化工艺的优化条件为臭氧通量80 mg/h、初始NF质量浓度15.0 mg/L、反应温度25℃、初始NF溶液p H 5.0;在该优化条件下反应60 min时,TOC去除率达51.5%,较单独臭氧氧化的32.5%和单独活性炭吸附的11.5%有明显改善;在活性炭催化臭氧氧化工艺中臭氧氧化与活性炭吸附之间存在一定的协同作用,活性炭具有较好的催化活性;活性炭催化臭氧氧化工艺对NF的去除主要是基于臭氧的直接氧化作用。     

Ti-Cu-Mn复合物负载石墨烯催化剂制备及其降解二甲苯性能

采用水热法制备了4种不同摩尔比的Cu-Mn-Ti/GS复合物催化剂,利用固定式反应床评价了其对二甲苯的催化氧化性能,并对催化剂进行了BET、XRD、SEM、TEM、XPS等表征,探讨了其对二甲苯的降解动力学.结果表明,当催化剂的Cu、Mn含量增加时,其比表面积有所降低,总孔容也降低,降解活性减小.催化剂中Cu-Mn呈现Cu_(1.5)Mn_(1.5)O_4和CuMn_2O_4两种晶格,活性组分有Cu~+、CuMn O和TiO_2.石墨烯载体的稳定性较好,Ti-Cu-Mn/GS(1∶1∶1)催化剂的颗粒分布较均匀,粒径也较小,降解二甲苯的T50为97℃,表现出较好的低温催化降解性能.催化剂对二甲苯的催化氧化降解过程符合一级反应动力学方程.     

基于CWPO法处理垃圾渗滤液的CuO/TiO_2催化剂的制备及其性能研究

采用过量浸渍的方法制备CuO/TiO_2催化剂,以垃圾转运站的渗滤液为对象评价催化剂的活性及稳定性。采用XRD、SEM、BET对催化剂进行了表征,并利用催化湿式氧化法处理垃圾渗滤液。考察了制备过程中煅烧温度、煅烧时间、负载比以及浸渍液浓度对垃圾渗滤液处理效果的影响。结果表明:煅烧温度为300℃,煅烧时间为2 h,负载比为16.5%,浸渍液浓度为0.8 mol/L条件下,渗滤液COD去除率达到78.6%,脱色率达到88.2%。     

低温条件下烟气脱硫脱硝技术的研究与应用

摘 要:分析了我国工业锅炉、水泥玻璃窑炉、化工厂和酸洗设备面临的烟气脱硫脱硝难题,针对低温SCR催化剂开发情况和应用实例,介绍了我国低温SCR技术的发展;综述了活性焦法低温烟气脱硫脱硝工艺和湿法有机催化氧化烟气脱硫脱硝技术的工艺原理、流程和技术特点,并通过工程案例进行了运行经济评估。     

Effect of iron ion configurations on Ni2+ removal in electrocoagulation

Electrocoagulation (EC) has been widely used to treat the heavy metal wastewater in industry. A novel process of sinusoidal alternating current electrocoagulation (SACC) is adopted to remove Ni²⁺ in wastewater in this study. The morphology of precipitates and the distribution of the main functional iron configurations were investigated. Ferron timed complex spectroscopy can identify the monomeric iron configurations [Fe(a)], oligomeric iron configurations [Fe(b)] and polymeric iron configurations [Fe(c)]. The optimal operating conditions of SACC process were determined through single-factor experiments. The maximum Ni²⁺ removal efficiency [Re(Ni²⁺)] was achieved under the conditions of pH₀=7, current density (j) = 7 A/m², electrolysis time (t) = 25 min, c₀(Ni²⁺) = 100 mg/L. At pH=7, the proportion of Fe(b) and Fe(c) in the system was 50.4 at.% and 23.1 at.%, respectively. In the SACC process, Fe(b) and Fe(c) are the main iron configurations in solution, while Fe(c) are the vast majority of the iron configurations in the direct current electrocoagulation (DCC) process. Re(Ni²⁺) is 99.56% for SACC and 98.75% for DCC under the same optimum conditions, respectively. The precipitates produced by SACC have a high proportion of Fe(b) configurations with spherical α-FeOOH and γ-FeOOH structures which contain abundant hydroxyl groups. Moreover, it is demonstrated that Fe(b) has better adsorption capacity than Fe(c) through adsorption experiments of methyl orange (MO) dye. Fe(a) configurations in the homogeneous solution had no effect on the removal of nickel.     

Nickel recovery from electronic waste II Electrodeposition of Ni and Ni–Fe alloys from diluted sulfate solutions

This study focuses on the electrodeposition of Ni and Ni–Fe alloys from synthetic solutions similar to those obtained by the dissolution of electron gun (an electrical component of cathode ray tubes) waste. The influence of various parameters (pH, electrolyte composition, Ni²⁺/Fe²⁺ ratio, current density) on the electrodeposition process was investigated. Scanning electron microscopy (SEM) and X-ray fluorescence analysis (XRFA) were used to provide information about the obtained deposits’ thickness, morphology, and elemental composition. By controlling the experimental parameters, the composition of the Ni–Fe alloys can be tailored towards specific applications. Complementarily, the differences in the nucleation mechanisms for Ni, Fe and Ni–Fe deposition from sulfate solutions have been evaluated and discussed using cyclic voltammetry and potential step chronoamperometry. The obtained results suggest a progressive nucleation mechanism for Ni, while for Fe and Ni–Fe, the obtained data points are best fitted to an instantaneous nucleation model.     

催化燃烧法处理炼油厂隔油池废气

在隔油池废气催化燃烧处理中试装置上 ,采用蜂窝状 Pt、Pd、Ce多组分催化剂 ,在空速 40 0 0 0 h- 1 、反应器入口温度 2 5 0℃以上、进气总烃体积分数 10 0 0× 10 - 6 ～ 6 0 0 0× 10 - 6 条件下 ,可以使总烃去除率达到 96 %～ 99% ,净化排气总烃体积分数小于 10 0× 10 - 6 ,无恶臭气味     

烟气脱硫石膏催化还原为硫化钙的研究

采用Fe-Ni复合催化剂,在温度650℃条件下即可将烟气脱硫石膏催化还原为硫化钙,还原率达95%以上。研究了反应温度、催化剂加入量及还原气体含量因素对还原反应的影响。